During operations at a drilling rig, a service rig or an offshore rig, it is frequently necessary to move lengths of pipe (referred to as pipe joints) between the rig floor and a pipe storage area adjacent to the rig. A pipe joint may be moved to and from the rig floor by attaching a winch cable from a winch on the rig to the pipe joint and then raising or lowering the pipe joint using the rig winch. This procedure is time consuming and potentially dangerous for the rig crew.
Various apparatus and methods exist in the prior art which are directed at automating the procedure of moving pipe joints to and from the rig floor. A pipe handling apparatus of this type is frequently referred to as a “catwalk”.
Some prior art pipe handling apparatus of the catwalk type and associated methods are described in U.S. Pat. No. 4,386,883 (Hogan et al); U.S. Pat. No. 4,403,898 (Thompson); U.S. Pat. No. 4,494,899 (Hoang et al); U.S. Pat. No. 6,994,505 (Hawkins); U.S. Pat. No. 7,163,367 (Handley); U.S. Pat. No. 8,016,536 (Gerber et al); U.S. Pat. No. 8,033,779 (Gerber et al); U.S. Pat. No. 8,052,368 (Littlewood et al); U.S. Pat. No. 8,215,887 (Fikowski et al); U.S. Patent Application Publication No. US 2005/0238463 (Smith); U.S. Patent Application Publication No. US 2008/0263990 (Morelli et al); U.S. Patent Application Publication No. US 201 1/0070054 (Crossley et al); U.S. Patent Application Publication No. US 2012/0027541 (Gerber et al); U.S. Patent Application Publication No. US 2012/0121364 (Taggart et al); Canadian Patent No. 2,224,638 (Morelli et al); Canadian Patent No. 2,431,213 (Handley et al); Canadian Patent No. 2,431,229 (Shiels et al); Canadian Patent No. 2,510,137 (Wells); Canadian Patent Application No. 2,476,109 (Smith); and Canadian Patent Application No. 2,713,676 (Crossley et al).
In conventional catwalk-type pipe handling apparatuses, a forward lifting assembly may typically by coupled to the lift carriage at a pivot point. The pivot point typically has a single defined position along the longitudinal axis of the lift carriage (at a point between the rear carriage end and the forward carriage end). Thus, while a forward lifting assembly may expand and retract, the overall range of positions possible for the forward carriage end may be limited.
Canadian Patent No. 2,444,446 describes a catwalk system comprising a boom and pivoting member. The boom and pivoting member define respective pluralities of ports, with each port of the boom being aligned with a corresponding port in the pivoting member when the boom is in a fully lowered position. Thus, when the boom is lowered, a pin may be placed in the desired pair of ports. Thus, the position of the pivot connection between the forward lifting assembly and the lift carriage is has a limited set of pre-defined positions available. The boom movement, thus, will be limited to a pre-defined, discrete set of arcs, with each arc corresponding to one of the pivot positions and rotation of the lift arm through its rotational range of motion. In addition, changing the selected pivot position may require first lowering the boom so that the pin may be safely removed and placed in a new position.
Thus, there is a need for improved apparatuses for handling pipes or other tubulars.